Collaborative Research: Seismicity of the Equatorial Mid-Atlantic Ridge and its Large Offset Transforms

合作研究：赤道大西洋中脊的地震活动及其大偏移量变换

• 批准号: 1062238
• 负责人: Robert Dziak
• 金额: $ 39.12万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1062238&HistoricalAwards=false
• 关键词: Collaborative; Research; Seismicity; Equatorial; Mid

The sizes and locations of earthquakes recorded by eight hydrophones moored in the Equatorial Atlantic Ocean provide an unparalleled view of the seismicity of the poorly understood slow-spreading Mid-Atlantic Ridge in this region. The data also allow testing of the idea that earthquakes can be predicted at ocean transform faults, and they provide insight into how triple junctions (where three tectonic plates meet) work. The Equatorial Atlantic seafloor has not been studied extensively but is interesting for many reasons. First, the Mid-Atlantic Ridge axis is offset on some of the longest transform faults in the oceans. As an example, the Romanche transform is greater than 900 km long. In places, the transform offsets are so large that the total length of the transform faults is longer than the total length of the ridge axis. These fracture zones are extremely rugged, are important conduits for bottom water moving between the North and South Atlantic Ocean, and probably act as physical barriers blocking the transport of hydrothermal vent fauna along the ridge axis. The Equatorial Atlantic transforms are ideal for testing the short-term predictability of earthquakes at ocean transform faults and the results may help in understanding earthquakes on continental faults. A second interesting aspect of the region is that it contains the triple junction where the North America, South America, and Africa tectonic plates meet. The exact location of the triple junction is still a matter of debate, and this study will help to define its location. Third, the location of the plate boundary between the North America and South America plates is not known even though there is motion between the plates. The earthquakes recorded by the hydrophones provide important new information about the motion of these two plates, and how and where that motion is taking place. The hydrophone array also records a variety of natural and man-made noises and will facilitate a wide-range of studies beyond the scope of the proposed work. Examples include the use of ambient sound measurements to study various climate research topics, including estimating wave heights, rainfall intensity and wind speed during hurricanes. In addition, recorded whale vocalizations allow the distribution and migration of these animals to be tracked throughout the Equatorial Atlantic Ocean.

停泊在赤道大西洋的八个水听器记录的地震的大小和位置提供了一个无与伦比的视图的地震活动的知之甚少，缓慢蔓延的中大西洋海岭在这一地区。 这些数据还允许测试海洋转换断层可以预测地震的想法，并提供了对三重连接（三个构造板块相遇）如何工作的见解。赤道大西洋海底尚未得到广泛研究，但由于许多原因而令人感兴趣。 第一，大西洋中脊轴在海洋中一些最长的转换断层上偏移。作为一个例子，Romanche变换大于900 km长。在某些地方，转换断层的偏移量很大，以至于转换断层的总长度比山脊轴的总长度还要长。这些断裂带极为崎岖，是底层水在北大西洋和南大西洋之间流动的重要通道，可能是阻挡热液喷口动物沿着洋脊轴线迁移的物理屏障。赤道大西洋转换是检验海洋转换断层地震短期可预测性的理想方法，其结果可能有助于了解大陆断层地震。该地区的第二个有趣的方面是，它包含了北美，南美和非洲构造板块相遇的三重连接点。三重连接点的确切位置仍然是一个有争议的问题，这项研究将有助于确定其位置。第三，北美板块和南美板块之间的板块边界的位置是不知道的，即使有运动之间的板块。水听器记录的地震提供了关于这两个板块运动的重要新信息，以及运动如何以及在哪里发生。 水听器阵列还记录各种自然和人为噪音，并将促进拟议工作范围以外的广泛研究。 实例包括使用环境声测量来研究各种气候研究课题，包括估计飓风期间的波高、降雨强度和风速。此外，有记录的鲸鱼叫声使这些动物的分布和迁移在整个赤道大西洋被跟踪。